261957407 has 2 divisors, whose sum is σ = 261957408. Its totient is φ = 261957406.

The previous prime is 261957343. The next prime is 261957413. The reversal of 261957407 is 704759162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261957407 - 2⁶ = 261957343 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261957467) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130978703 + 130978704.

It is an arithmetic number, because the mean of its divisors is an integer number (130978704).

Almost surely, 2^261957407 is an apocalyptic number.

261957407 is a deficient number, since it is larger than the sum of its proper divisors (1).

261957407 is an equidigital number, since it uses as much as digits as its factorization.

261957407 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 105840, while the sum is 41.

The square root of 261957407 is about 16185.0983005974. The cubic root of 261957407 is about 639.8481141849.

The spelling of 261957407 in words is "two hundred sixty-one million, nine hundred fifty-seven thousand, four hundred seven".